-아/어야 해요: Have to and Must in Korean

Use -아/어야 해요 when something is necessary:

• 가야 해요. → I have to go.
• 공부해야 해요. → I have to study.
• 약을 먹어야 해요. → I need to take medicine.

The exact English can be “have to,” “need to,” or “must.” The Korean idea is necessity.

For more patterns around obligation, browse the grammar encyclopedia and keep the core grammar map open.

How to form it

Start with the verb stem and attach -아야 해요 or -어야 해요.

Examples:

• 가다 → 가 + 아야 해요 → 가야 해요
• 먹다 → 먹 + 어야 해요 → 먹어야 해요
• 읽다 → 읽 + 어야 해요 → 읽어야 해요
• 하다 → 해야 해요

The same 아/어 vowel logic appears across Korean conjugation, so review the present-tense reference if the choice still feels unfamiliar.

Everyday examples

• 내일 일찍 일어나야 해요. → I have to wake up early tomorrow.
• 숙제를 해야 해요. → I have to do my homework.
• 지금 가야 해요. → I have to go now.
• 한국어를 더 연습해야 해요. → I need to practice Korean more.
• 금요일까지 보내야 해요. → I have to send it by Friday.

That last sentence combines obligation with 까지.

해요 vs 돼요 variants

You will also hear -아/어야 돼요. In many everyday contexts it expresses the same basic necessity:

• 가야 해요.
• 가야 돼요.

Both can mean “I have to go.” Register and speaker preference vary, so recognize both rather than treating one as a completely different grammar point.

Do not negate it mechanically for “do not have to”

English makes “have to” negative by adding “do not.” Korean usually uses a different construction for permission/non-necessity.

So avoid assuming 안 가야 해요 automatically means “I do not have to go.” Depending on context, it can be interpreted differently.

For beginners, learn these as separate ideas:

• 가야 해요 → have to go
• 가지 않아도 돼요 → do not have to go / it is okay not to go

Asking about necessity

• 꼭 가야 해요? → Do I really have to go?
• 오늘 해야 해요? → Do I have to do it today?
• 몇 시까지 와야 해요? → By what time do I have to come?

These are useful practical questions at work, school, appointments, and classes.

Common mistakes

Forgetting the 아/어 connection

Treat -아/어야 해요 as a conjugated ending, not a word you place after the dictionary form.

Wrong: 먹다야 해요.

Correct: 먹어야 해요.

Confusing desire and obligation

• 공부하고 싶어요. → I want to study.
• 공부해야 해요. → I have to study.

Review -고 싶어요.

Mini practice

Convert to “have to.”

1. 가다 → 가야 해요.
2. 먹다 → 먹어야 해요.
3. 공부하다 → 공부해야 해요.
4. 준비하다 → 준비해야 해요.

Then say one real thing you have to do tomorrow.

Continue learning

• Grammar encyclopedia
• Present tense formation
• -고 싶어요
• 부터 vs 까지
• Grammar hub

Once this form becomes automatic, you can describe schedules, responsibilities, and rules with very little vocabulary.